1. Field of the Invention
The present invention relates to an irradiating apparatus for performing irradiation with beam light using a semiconductor laser as a light source, a semiconductor device manufacturing apparatus for manufacturing a semiconductor device using irradiation with the beam light, a semiconductor device manufacturing method, and a display device manufacturing method.
2. Description of the Related Art
It is known that when an active matrix type liquid crystal display device, an organic electroluminescent display device (hereinafter referred to as an “organic EL display”) using an organic electroluminescent element (hereinafter referred to as an “organic EL element”), or the like is manufactured, a thin silicon film is subjected to annealing treatment using continuously oscillating laser beam light to form a circuit element such as a thin film transistor (hereinafter abbreviated to a “TFT”) or the like by polycrystalline silicon. The annealing treatment using the laser beam light partly irradiates the thin silicon film, so that increases in temperature of the whole of a substrate can be avoided and a glass substrate can be used as the substrate.
It is also known that output beam light from an irradiating optical system of an annealing apparatus is desirably a linear beam in order to achieve higher throughput when the annealing treatment using the laser beam light is performed. It is further known that in order to form uniform polycrystalline silicon by such annealing treatment, a so-called uniformizing optical system is desirably formed in a direction of a major axis of the linear beam to thereby suppress nonuniformity of irradiation of the thin silicon film in the direction of the major axis.
FIG. 12 shows an example of configuration of an irradiating optical system in a direction of length of an emitter (hereinafter referred to as a “slow axis direction”), which is an example of an existing technique using a broad area type semiconductor laser. In the irradiating optical system shown in FIG. 12, a luminous flux from a semiconductor laser 71 is collimated by a collimator lens 72, and a resulting far field pattern FFP(1) is projected into a far field pattern FFP(2) by an image forming lens 73. A luminous flux in a direction (hereinafter referred to as a “fast axis direction”) perpendicular to the slow axis direction is condensed in a near field pattern NFP. When reaching the far field pattern FFP(2), the beam is made to have a same beam diameter in each of the directions (the slow axis direction and the fast axis direction). Thereby, even when an object to be irradiated which object is placed in the far field pattern FFP(2) is shifted in a direction of an optical axis, change in beam diameter is small and depth of focus is large (see Japanese Patent Laid-open No. 2000-305036, for example).